1. Field of the Invention
The present invention relates to a self-retaining catheter that is arranged to be retained in a blood vessel or the like of a patient and to permit a medical fluid, for example such as a carcinostatic, to be injected on a periodic basis, and an inserting apparatus thereof.
2. Related Background Art
For administration of such a medical fluid as a carcinostatic, for example, the medical fluid was administered into a blood vessel conventionally by use of an injection syringe or a drip. In that case, the medical fluid circulated through blood vessels in the body, and thus there was the fear of damaging the normal cells in addition to cancerous cells.
Under such circumstances, attempts have been made to achieve such techniques as to percutaneously insert a catheter into a blood vessel, locate the leading end of this catheter at an arterial inlet to an organ affected by cancer, and directly inject the medical fluid into the organ affected by cancer, thereby accomplishing a prominent carcinostatic effect even with a small dose of the medical fluid.
In this case, after the catheter was set so that the leading end thereof was located at the arterial inlet to the target organ, injection of the medical fluid was carried out while the base side of the catheter was fixed to the patient's body so as to prevent the leading end of the catheter from shifting from the position.
In order to prevent the medical fluid from flowing into arteries branched to the other normal organs, embolization coils or the like were inserted into inlets of the arteries branched to the other normal organs so as to temporarily obstruct the blood flow, so that the medical fluid could flow into only the organ affected by cancer.
On the other hand, there are conventionally known catheters having the structure capable of retaining themselves not only in the blood vessels, but also in tubular organs of the human body, and an example of such catheters is the one described in Japanese Patent Application Laid-open No. 5-192389, in which the catheter is comprised of an outside tube, an inside tube, and a reinforcement interposed between them, and in which a flap projecting to engage an inner wall of a tubular organ of the human body is mounted on the periphery of the leading end of the outside tube.
Another known example is the one described in Japanese Utility Model Application Laid-open No. 5-86355, in which a plurality of fins are arranged at intervals on the periphery of the leading end or an intermediate section of the catheter so as to act as a cushion, a seal, a stopper, and a protector.
In treatments by the conventional method for locating the leading end of the catheter at the inlet of the artery to the affected organ as a target and directly feeding the medical fluid into the target organ, there sometimes occurred, however, accidents that the position of the leading end of the catheter shifted because of a body motion, such as tossing, of the patient on the occasion of injection of the medical fluid, so as to cause the medical fluid to flow into the other organs than the target organ, though the base side of the catheter was fixed to the patient's body.
Further, it was not easy to apply the self-retaining catheter described in Japanese Patent Application Laid-open No. 5-192389 to a tubular organ comprised of a narrow and thin wall, such as a blood vessel, because the flap projecting from the periphery of the leading end of the catheter tended to damage the internal wall of the tubular organ.
With the self-retaining catheter described in Japanese Utility Model Application Laid-open No. 5-86355, the fins also tended to damage the internal wall of the tubular organ and in applications to the blood vessels or the like, it was difficult to retain the catheter over the long term, because the fins obstructed the blood flow.